21313222081 has 2 divisors, whose sum is σ = 21313222082. Its totient is φ = 21313222080.

The previous prime is 21313222057. The next prime is 21313222093. The reversal of 21313222081 is 18022231312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21282141456 + 31080625 = 145884^2 + 5575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313222081 - 2⁹ = 21313221569 is a prime.

It is a super-2 number, since 2×21313222081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21313222781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656611040 + 10656611041.

It is an arithmetic number, because the mean of its divisors is an integer number (10656611041).

Almost surely, 2^21313222081 is an apocalyptic number.

It is an amenable number.

21313222081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313222081 is an equidigital number, since it uses as much as digits as its factorization.

21313222081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

Adding to 21313222081 its reverse (18022231312), we get a palindrome (39335453393).

The spelling of 21313222081 in words is "twenty-one billion, three hundred thirteen million, two hundred twenty-two thousand, eighty-one".